1. Field of the Invention
The present invention is related to device characterization methods and circuits, and more particularly to a method and system for determination of parameter variation statistics for devices within a test array.
2. Description of Related Art
Parameter variation/process variation has become increasingly significant as processes have shrunk. Simulation can only provide a level of confidence in the overall yield of design or production, but testing is typically required to determine the true variation of device parameters for particular geometries and processes.
For the reasons given above, test arrays are typically fabricated either on production wafers or as independent test models, to characterize devices for both design verification and production testing purposes. The determination of process and/or parameter variation statistics is a time-consuming and computationally intensive process, especially when a large number of test devices must be evaluated. On the order of 100 samples per computed distribution must be collected over the range of operating parameters to be measured in order to provide a reasonably accurate model, and then the statistics must be computed from the sample values.
Therefore, it would be desirable to provide a faster method and test system for determining parameter variation statistics.